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Grade: 10
        
A car covers its outward journey at 40kmph. It is towed back, over exactly the same distance at 10mph. What is the average speed over the entire journey?
 
A)12mph B)14mph C)15mph D)20mph
 
 
Ans :D
9 months ago

Answers : (2)

Arun
13867 Points
							
Dear student
 
we can apply the formula 2xy/(x+y) for average speed.
Hence
 
Avg speed = 2*40*10/(40+10) = 800/50 = 16 kmph
 
Regards
Arun (askIITians forum expert)
9 months ago
Arun
13867 Points
							
 
Sorry,the above soltuion is incorrect due to not taking conversion
 
40 kmph = 40/1.6 mph = 24.85 mph
 
Now avg speed = 2*24.85*10/34.85 = 14.26 mph
 
Hence option B is correct
9 months ago
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